With Advanced LIGO's recent direct observation of gravitational waves, the current era of advanced gravitational wave interferometers is the most exciting period in the history of gravitational wave astrophysics. Efforts in detector characterization such as those undertaken in this project and multi-messenger astronomy will enhance LIGO science and its ties to the rest of the astronomical community while providing many opportunities for student engagement. Researchers supported by this grant are involving students at various levels of education, from elementary class visits, to high school research internships, to the first physics PhD candidate on Embry-Riddle's Prescott campus. Undergraduate research remains a particular focus at Embry-Riddle Aeronautical University, and multiple senior theses and other undergraduate projects will benefit from NSF financial support. Embry-Riddle's LIGO group continues to increase its outreach efforts, taking advantage of opportunities in northern Arizona, including close proximity to the Navajo reservation.
Identification of a gravitational wave transient consistent with the time and location of an electromagnetic (e.g. optical or radio) signal will provide a wealth of information about the source that would not be available through means of a single astrophysical messenger. Core Collapse Supernovae are an exciting target for this multi-messenger astronomy approach. The combination of a gravitational wave and optical observation from the same supernova would address a number of open questions in astrophysics, including the mechanism of the explosion itself as well as fundamental questions about neutrino interactions and the neutron star equation of state. Another area of multi-messenger astronomy that LIGO has begun to investigate is the search for gravitational waves in coincidence with astrophysical sources of radio transients of duration on the scale of milliseconds. These could be emitted simultaneously with gravitational waves due to scenarios ranging from neutron star asteroseismology to cosmic string cusps. Gravitational wave astronomy has the potential to shed light on several types of radio emission, possibly including fast radio bursts. The search for gravitational wave bursts is made more difficult by the presence of transient terrestrial background, resulting from a combination of environmental disturbances and behavior of the interferometers themselves. Understanding these environmental disturbances and removing them from interferometric data is critical in conducting sensitive searches for gravitational waves. This grant funds substantial effort in identifying and mitigating the non-astrophysical background in the interferometers and application of vetoes to eliminate them through participation in LIGO's detector characterization working group.
